∆ Time Travel In Einstein's universe.

An extremely well written and informative book, which given the subject naturally starts straight from the assumption that time just exists.

I agree and disagree with these opening remarks, in that I don't think Einstein did prove that 'the Future' actually exists, and that we could (at least theoretically) travel into it.

I don't think we can travel to the future, because I don't think the existence of the future has been proven. I think what Einstein showed was not 'time travel into the future' (although he may have expressed it as that), but that 'moving things change more slowly than static things'.

Therefore, if you do travel to a distant star and return (P33) - during your journey you will change more slowly than say an identical twin remaining at rest on Earth. If Time exists, and if the future exists, then this is indeed similar or identical to travelling into the future. But if time and the future don't exist then this is just one thing changing slower than another 'now'.

But, if (as i think we all constantly observe) there is only now, and things just move and change now, then experiments like this only show that if you are changing an objects location, you are 'using up' some of its local change.

I agree, that the answer to the question of 'whether we can travel to the past' would give us insights into how the universe works - But i think the answer to this question is....

-No, we cannot travel into the past, because there is no proof that time exists, and specifically no proof that as things move and change they create any other 'past' behind them other than the physical trail, or wake of evidence made physically 'behind them' as the move through their surroundings.

In other words there is no proof of a 'temporal past' also existing.

I think what Einstein showed us was that it makes sense to assume there is a maximum speed limit in the universe (becasue we dont clearly observe instantaneous reactions - Quantum entanglement not being particulary clear at least to me).

Assuming, the maximum speed of objects - or the maximum speed of 'the
consequences of events' - is the speed of light. Then, if
you could surpass this (unsurpassable) speed, you could arrive in paces 'be-fore' - i.e.
physically ahead of - the consequences of your actions.

This is
similar to saying that if you post a letter to your lover saying 'It's
over!' then the decision has been made, and is out there. So the deed has
been 'done'.

But, if having posted the letter, you jump into a
car, and head to your lovers home - overtaking the letter on the way - then
he, or she, will greet you as if nothing had happened. Not because you went back in time, but just because you went faster thant the consequences of your actions. The bad news is - the bad news is still heading towardsw you both. You can run, but you cant hide.

So while the answer to the question 'Can we travel into the past?' may be 'no', the insight it reveals is that, at least 'now', everything is just here now. This forces us to look at all the evidence around us in a very different mind set, it highlights for example that perhaps we never actually see things 'begin' or 'end'.

- we only see things 'come together' from existing matter and 'fall apart' into different forms. We also only ever see thing enter and leave our field of view. Also, as humans, we only ever see existing matter 'come together' to form 'new' people - and 'fall apart' - making them seem to disappear.

So, if there is no sense behind the idea of time, and we never see things begin or end - then perhaps the question 'how did the universe begin?' should be changed.

Just what the replacement question should be, or what its answer is, is not in the scope of my work.

All I have set out to do focus intently one one issue, and highlight what I think may be one 'wrong piece' in the jigsaw puzzle of our understanding of the universe. A piece that most people seem to think is correct, but around which other pieces don't seem to fit well.

I have to reiterate, that if what I am suggesting about time and timelessnes is correct then this is not such a bad thing. no great swaths of work need be discarded or rewritten, but they may be reinterpreted (in a timeless sense) eliminating incorrect conclusions - but also squeezing out unseen answers, understandings and possibilitys on the way.